The present invention relates, in general, to a horizontal injection molding machine with a turning device rotatable about a vertical axis for half-molds.
A horizontal injection molding machine of this type is known, for example, from WO 03/013824 having a turning device provided for the half-molds and supported in a stationary frame which is mounted to a machine bed and traversed by the tie bars of the injection molding machine. This arrangement has the drawback that, on one hand, only a two-step operation is possible as a consequence of the frame construction for the stationary tuning unit, since the half-molds which are supported on the turning device are inaccessible from the side so that there is no possibility to carry out from the side of the machine additional processing steps such as, for example, removal of finished molded parts or placement of inserts in half-molds that still undergo molding, while injection just takes place in further mold pairs. In addition, removal of the molded parts requires access between both half-molds, i.e. there is no easy accessibility. A further drawback of this apparatus is the limitation of the maximum size of the turning half-molds that can be used as a result of the size of the frame. This is substantially restrictive especially when large-area injection-molded part are produced.
JP 06254906 A also discloses an injection molding machine with turning device, having tie bars that are extend through a frame of the turning device. The moving mold platens are moved here via hydraulic drive cylinders which are articulated to the side of the frame of the turning device and must be attached to the mold platens in symmetry to a longitudinal axis of the injection molding machine to ensure sufficient centering. In an opening position, the mold platens can be moved apart far enough to allow withdrawal of the tie bars from one of the two mold platens. This apparatus has also the drawback that the size of the frame limits the size of the useable half-molds, and that furthermore accessibility to the molds is made difficult by the frame and a two-step operation is no longer possible.
It would therefore be desirable and advantageous to provide an improved horizontal injection molding machine which obviates prior art shortcomings and is useable with large-sized half-molds even for large-scale machines, while allowing for a rotary mode as well as reversible four-step mode, and which is also applicable in a clean room environment, while still being reliable and stable in operation and able to produce highly precise, large-size multicomponent plastic parts.